Mayo found that rather than deny a false claim, it is better to make a completely new assertion that makes no reference to the original myth. Rather than say, as Sen. Mary Landrieu (D-La.) recently did during a marathon congressional debate, that "Saddam Hussein did not attack the United States; Osama bin Laden did," Mayo said it would be better to say something like, "Osama bin Laden was the only person responsible for the Sept. 11 attacks" -- and not mention Hussein at all.
But sometimes it is not the best policy to ignore a faulty view.
Another recent study found that when accusations or assertions are met with silence, they are more likely to feel true, said Peter Kim, an organizational psychologist at the University of Southern California. He published his study in the Journal of Applied Psychology.
So basically we’re damned if we do and damned if we don’t. I would give examples based on anti-Catholic falsities but I don't want to reinforce them. I recommend reading the whole article to get the details.